环境：linux操作系统， ruby1.9.3+rails3.2
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如果出现下面问题：
however, when i try to activate the server with ‘rails s’ or ‘rails server’ , I still get: /usr/lib/ruby/gems/1.9.1/gems/execjs-1.3.0/lib/execjs/runtimes.rb:50:in `autodetect’: Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes. (ExecJS::RuntimeUnavailable) from /usr/lib/ruby/gems/1.9.1/gems/execjs-1.3.0/lib/execjs.rb:5:in `<module:ExecJS>’ from /usr/lib/ruby/gems/1.9.1/gems/execjs-1.3.0/lib/execjs.rb:4:in `<top (required)>’ from /usr/lib/ruby/gems/1.9.1/gems/coffee-script-2.2.0/lib/coffee_script.rb:1:in `require’ from /usr/lib/ruby/gems/1.9.1/gems/coffee-script-2.2.0/lib/coffee_script.rb:1:in `<top (required)>’ from /usr/lib/ruby/gems/1.9.1/gems/coffee-script-2.2.0/lib/coffee-script.rb:1:in `require’ from /usr/lib/ruby/gems/1.9.1/gems/coffee-script-2.2.0/lib/coffee-script.rb:1:in `<top (required)>’ from /usr/lib/ruby/gems/1.9.1/gems/coffee-rails-3.2.1/lib/coffee-rails.rb:1:in `require’ from /usr/lib/ruby/gems/1.9.1/gems/coffee-rails-3.2.1/lib/coffee-rails.rb:1:in `<top (required)>’ from /usr/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:68:in `require’ from /usr/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:68:in `block (2 levels) in require’ from /usr/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:66:in `each’ from /usr/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:66:in `block in require’ from /usr/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:55:in `each’ from /usr/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler/runtime.rb:55:in `require’ from /usr/lib/ruby/gems/1.9.1/gems/bundler-1.0.21/lib/bundler.rb:122:in `require’ from /home/john/rails_space/config/application.rb:7:in `<top (required)>’ from /usr/lib/ruby/gems/1.9.1/gems/railties-3.2.0/lib/rails/commands.rb:53:in `require’ from /usr/lib/ruby/gems/1.9.1/gems/railties-3.2.0/lib/rails/commands.rb:53:in `block in <top (required)>’ from /usr/lib/ruby/gems/1.9.1/gems/railties-3.2.0/lib/rails/commands.rb:50:in `tap’ from /usr/lib/ruby/gems/1.9.1/gems/railties-3.2.0/lib/rails/commands.rb:50:in `<top (required)>’ from script/rails:6:in `require’ from script/rails:6:in `<main>’
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解决办法：
gemfile文件中添加如下两句代码：
gem ‘execjs’gem ‘therubyracer’
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运行：
bundle install
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吃水不忘挖井人。
